Railway traffic controlling system



June 1, 1937. D. w. MERS EREAU RAILWAY TRAFFIC CONTROLLING SYSTEM Filed Dec. 5, 1930 W 0% m TQM MQ Ir NW SW F mm I TV m8. n QWJ v F ne 859R x u u G 6Q ki n? w 9. =0 I a c Hu= n? LL 2 R m. (E H mm m u 3 14 U r 0m. l tw L o w m m Q Ma 4 m 2 INVENTOR BY '/ATTORNE'Y Patented June 1, 1937 UNE'E'EQ STEES PATENT FHQE Donald W. Mersereau, Rochester, N. Y., assignor to General Railway Signal Company, Rochester, N. Y.

Application December 5, 1930, Serial No. 500,297

20 Claims.

This invention relates to a system for controlling a distant track switch, and more particularly to means for protecting against operation of such switch in the face of an aproaching train.

A switch operated by a switch machine controlled from a central oflice may be protected against operation in the face of an approaching train by what is generally known as time looking, in which case the switch may only be operated if all of the signals associated with such switch are at stop and have been at stop for a period of time, preferably two or three minutes, so that if there was a train approaching when the signals were put to stop, this train has either passed over the switch or has come to a stop before it reached the switch, suitable detector track circuit locking of course being provided to guard against operation of the switch machine when a train is actually standing on or passing over the switch points. A system of time locking of this character is disclosed in the prior application of R. M. Phinney, Ser. No. 463.940 filed June 26, 1930. Another form of approach locking resides in the provision of means for locking the switch machine against operation in the event there is a train moving or occupying a certain approach zone, suitable means such as a time release of the type mentioned being provided for use in the event that there is such a train in the approach zone. Such approach locking means by itself is however inadequate, because a departing train in such approach zone would also lock the switch against movement. Furthermore, in order to allow a train to pass over the switch points it is necessary to clear a signal to permit such movement of the train, and as heretofore mentioned each clearing of a signal renders the approach locking means effective, so that it is desirable to employ means for cancelling or releasing the approach locking efiect when the signals have been put to stop by a passing train as distinguished from the placing of signals in the stop position manually from the central office, this distinction because the presence of a passing train assures against the approach of another train at speed. This could be accomplished by the provision of means effective to release the looking for each occupancy followed by non-occupancy of the detector track circuit, but this form of release is not entirely safe, because a workman might momentarily drop an iron or steel bar across the track rails and thereby release the locking of the switch machine.

In view of the foregoing and other important considerations, it is proposed in accordance with the present invention to provide means for lock- 5 ing the switch machine against operation when there is, a train occupying the approach section, and in addition thereto it is proposed to provide release means which is effective only for a moment after the detector track circuit is 10 cleared by a passing train and then only in the event that a directional stick relay picked up by such passing train is energized or providing that the track swich assumes the take-siding or restricted speed position.

More specifically, it is proposed to provide an approach locking stick relay which allows the switch machine to be operated only in the event that this relay is energized, and which relay can only be stuck up after all of the signals associat- 20 ed with the track switch are at stop, and which stick relay can only be picked up under any one of the following conditions, namely, the detector track circuit cleared after occupancy with a directional stick relay picked up, the detector 5 track circuit cleared after occupancy with the switch assuming the take-siding position or in the event that the approach section is unoccupied, and in addition to these methods of restoring the stick relay, this stick relay may be restored in a manner described in the application of Phinney heretofore referred to.

Other objects, purposes and characteristic features of the invention will in part be obvious from the accompanying drawing, and will in part be more specifically pointed out hereinafter.

In describing the invention in detail reference will be made to the accompanying drawing illustrating one particular embodiment of the invention.

In the drawing has been shown a portion of a single track section 0, and the end of a passing siding PS connected to said single track section 0 by a track switch S, which track switch is controlled through the medium of a switch machine SM. The track rails 9 are divided into blocks by insulating joints ID, to constitute track circuits including the detector track circuit having a track relay T and a track battery I l, the track circuit in the rear of signal I having a track relay '1 and a track battery l2 and the track circuit in advance of the signal 3, including the track battery l3. Although these tracks may constitute part of a double track railway system, in which trains moving only from right to left, it is preferably a portion of a single track railway system in which trains may move in either direction, and preferably this single track system is signalled by signalling apparatus of the absolute-permissive-block type. Proceeding on the assumption that the system is one of the absolute-permissive-block type, a train moving from left to right, or west to east, and into the single track section 0, is governed through the medium of the starting signal 2 or the dwarf starting signal 2 depending upon whether the train is moving off the main track or off of the side track of the passing siding PS, and similarly the movement of the trains from the single track section into the passing siding PS is governed by the entering signal I and the take siding signal I depending on the position of the track switch, there preferably being provided a permissive signal 3 in the rear of the signal I and a permissive signal 4 in advance of the signal 2. The switch machine SM is preferably controlled from a central control office conventionally designated by the dotted rectangle DO, through the medium of the control relay CR controlled from this central ofiice' DO, such control relay being effective to control the switch machine only if the approach lock relay AL is energized, as conventionally indicated by the contact 62 in the control circuit for the switch machine SM.

The starting signal 2 as Well as the dwarf starting signal 2 are preferably controlled both manually and automatically in accordance with traflic conditions in advance, in a manner, for instance, as shown in the prior application of Wight Ser. No. 48,553, filed August 6, 1925, which manual control has for convenience 'not been illustrated in the drawing of the present application. This manual control of course permits clearing of the signals I, I 2 and 2 only in the event that traflic conditions in advance of the signals are clear. The automatic control of the signal 2 has been'conventionally illustrated by the dotted line I5, which signifies that the signal 2 may be cleared only in the event that the home-and-distant-relay 2HD is energized by current of positive polarity and then only in the event that the detector track circuit including the track relay T is unoccupied.

Attention is directed to the fact that the approach relay EA is energized only in the event that all of the blocks between the signals I and 3 are unoccupied and provided that one track circuit in the rear of this signal 3 is unoccupied, whereas the control for the relay 2HD includes only front contacts of the track relays of the blocks between the signals I and 3 the polarity of the energizing current depending upon the position of the signal 4. The condition of energization of the track relay is repeated through the track repeater relay TR,

" and the directional stick relay 2S for the signal 2 can be picked up only if the relays EA and TR are deenergized and the slow acting homeand-distant relay 2HD is energized, this occurring only when there is an east bound train entering the detector track circuit containing the track relay T Under normal traific conditions, that is when there are no trains around, and when the signals I, I and 2 and 2 are held at stop through suitable manual control (not shown), the homeand-distant relay 2HD is energized through the following circuit:beginning at the terminal of a suitable split, battery, signal contact I 9, front contact 20 of the relay T, wire 2|, front contact 22 of the relay T wire 23, winding of the relay 2HD to the mid-point C of said split battery. Also, the approach relay EA is normally energized through the following circuit:beginning at the terminal of a suitable battery, front contact 25 of the track relay T wire 26, front contact 21, track relay T wire 28, front contact 29 of the track relay T, wire 30, winding of the approach relay EA to the other terminal The control relay CR is preferably a polar relay of the magnetic stick type as conventionally shown by the black square, and is prefer- I ably controlled through the medium of any suitable form of selector system, such for instance as shown in the prior application of Preston and Hitchcock Ser. No. 455,304 filed May 24, 1930.

The track repeater relay TR is energized by a circuit including only the front contact 3| of the track relay T and a suitable source of current.

The approach locking relay AL is provided with three pick-up circuits and one stick circuit, which circuits may be traced respectively as follows:(1) beginning at the terminal of a suitable battery, front contact 35 of the track relay T, wires 36 and 31, front contact 38 of the approach relay EA, wires 39 and 40, winding of the relay AL, wire 4|, contact 42 of the signal i closed only when the signal is at stop, wire 43, contact 44 of the signal I closed only when signal I assumes a stop position, wire 45, contact 45 of the signal 2 closed only when this signal assumes a stop position, wire 41 and contact 43 of the signal 2 closed only when the signal 2 assumes a stop position, to the other terminal of the same battery; (2) beginning at the terminal of the same battery, front contact 35 of the track relay T, wires 36 and 50, front contact of the relay 28, wire 52, back contact 53 of the relay TR, wires 54 and 40, winding of the relay AL, wire 4I, contact 42, wire 43, contact 44, wire 45, contact 46, Wire 41', contact 48 to the other terminal of said battery; (3) beginning at the terminal front contact 35, wires 36, 50 and 56, switch machine contact 5! closed only when the track switch S assumes the take-siding position, wires 58 and 52, back contact 53 of the relay TR, wires 54 and 40, winding of the relay AL, and. elements 4|, 42, 43, 44, 45, 46, 41 and 48 to the other terminal of said battery; and (4) a stick circuit beginning at the terminal of said battery, front stick contact 60 of the relay AL, wires GI and 4B, winding of the approach relay AL and elements M, 42, 43, 44, 45, 46, 47 and 48 to the other terminal of said battery. It is believed that the operating characteristics and the underlying principles of the system are best understood by considering the operation of the system.

Operation Let us first assume that there is a train moving in a westwardly direction, that is from right to left in the single track section 0, and that his train has not yet reached the track section containing the track relay T It is readily apparent that the approach locking relay AL will be energized under the conditions assumed, and that the operator in the central ofiice DO may operate the switch machine. Under the conditions assumed the engineer will of course accept the signal 3 at caution and will be prepared to stop before he reaches the entering signal I.

Let us now assume that the west bound train under consideration has actually passed the signal 3, under which condition the approach relay EA as well as the home relay 2HD will assume their deenergized condition. Even under these conditions the operator in the central office D is permitted to operate the switch machine, through the medium of the control relay CR, this because the signals associated with the track switch S are all at stop and have remained there since the train accepted the approach permissive signal 3 at caution, the operator being able to operate the switch machine SM because the approach relay AL is still energized through its stick circuit including its contact I50 and the contacts 42, M, 46 and 48 of the signals associated with the track switch S. Let us, however, assume that the operator at the central oflice DO has cleared the signal I, and that the west bound train under consideration has already passed and accepted the signal 3 at clear, which cleared in response to the clearing of the signal I, and that thereafter the operator decides to have the train under consideration take the side track, and for that reason puts the signal I to stop and attempts to operate the switch machine SM. Under this condition the approach relay AL will have had its stick circuit interrupted during the time that the signal I was clear by reason of the opening of the contact 44 associated with this signal I. Also, the approach relay AL cannot be picked up at this time, because the contact 38 of the east approach relay EA is open, the front contact of the relay 2S is open, and the contact 51 associated with the track switch S is open, because this track switch S assumes the main track position. The approach relay AL consequently cannot be picked up and with the relay AL deenergized the switch machine SM cannot be operated, because the contact 62 of the approach relay AL prevents such operation. Under the condition assumed the operator in the central office DO cannot operate the switch machine SM until suitable time release means, such as disclosed in the application to Phinney above identified is employed, or other suitable release means such as a push button or a dual control selector contact as disclosed in the prior application of S. N. Wight, Ser. No. 120,423, filed July 3, 1926, is

employed and is operated by the train crew.

Let us now assume that there are two east bound trains, one of which is occupying the main track of the passing siding PS, and the other of which is occupying the side track, which side track may in fact comprise a diverging route, and that the operator wishes to allow the train occupying the main track to precede the other train through the single track section 0. Under this condition, the operator by suitable means, not shown, clears the signal 2 and allows the train on the main track to proceed into the single track section 0. With the signal 2 clear the approach locking relay AL is of course deenergized by reason of the opening of the contact 68 associated with the signal 2. As soon as the train occupying the main track passes by the signal 2 it will deenergize the detector track relay T and will cause the signal 2 to assume the stop position thereby re-closing the contact 58 associated with the signal 2. With the track relay T however deenergized the contact 35 of this track relay T is open, so that none of the pick-up circuits for the approach relay AL can be closed. If the train under consideration enters the track circuit containing the track relay T it will effect opening of the contacts 22 and 29 of this track relay T thereby simultaneously deenergizing the approach relay EA and the home-and-distant relay 2HD, but since the relay ZHD is slow acting the approach relay EA will assume its deenergized position before the relay 2I-ID moves from its energized position, thereby closing the following pick-up circuit for the directional stick relay 2S:-beginning at the terminal of a suitable battery, back contact 65 of the relay TR, wire 66, back contact 61 of the relay EA, wire 68, front contact 69 of the relay 2HD, wire I9, winding of the relay 2S, to the other terminal of said battery. The completion of this circuit will energize the stick relay 2S and after a short interval of time the contact 69 of the relay 2HD will drop to its retracted position, thereby, the stick relay 2S being slow acting, closing the following stick circuit for this relay 2S:--beginning at the terminal of said battery, front stick contact 'II of the relay 2S, wire I2, back contact 69 of the relay 2HD, wire I0, winding of the relay 28 to the other terminal of said battery. With the stick relay 28 now picked up and the signal 2 assuming the stop position, the approach looking relay AL will be picked up through the pickup circuit heretofore traced and including the front contact 35 of the track relay T, the train .in question having moved off of the detector track circuit, the front contact 5| of the stick relay 2S and the back contact 53 of the repeater track relay TR, this relay TR not yet having been energized long enough to open its back contact 53, this circuit of course including the contacts 42, 44, 46 and 48 of the four signals associated with the track switch S. It is thus seen that a departing train moving from the main track of the passing siding in an easterly direction will cancel or release the approach locking mechanism, that is, will pick up the approach relay AL. It is thus seen-that the operator is free tooperate the track switch S to allow the train occupying the side track to follow the first mentioned train into the single track section 0 without delay. In order to obtain this same look releasing feature for west bound trains a front contact of a directional stick relay for the signal I connected in multiple with the contact 5! of the stick relay 2S may be employed, if desired. Similarly, if an approach relay for trains approaching from the west is desired for obtaining approach locking for east bound approaching trains, such a relay may be provided and energized by a circuit extending one track circuit beyond the signal next in the rear of the signal 2, and a front contact of such approach relay may be included in series with the contact 38 of the approach relay EA, if desired.

Let us again assume that there are two east bound trains, one occupying the main track of the passing siding PS and the other occupying the side track of the passing siding PS, and let us assume that the operator wishes to allow the train on the side track to precede the other train into the single track section 0. In this case, the operator will move his lever L to the left hand position, thereby applying current of negative polarity to the control relay CR,

through the medium of the line wire 15', thereby operating the control relay CR to its left hand position and effect closure of the reverse circuit of the switch machine SM which may be-traced as followsz-beginning at the terminal of a suitable split battery, front contact 62 of the approach relay AL, wire l6, contact 71 of the control relay CR, reverse wire R, motor of the switch machine SM, to the midpoint C of said split battery. The closure of the circuit just traced will effect operation of the switch ma chine SM to the take-siding position, and when it has reached such position the circuit just traced will be broken within the switch machine SM, all in a manner understood by those skilled in the switch machine art. The operator will then clear the dwarf starting signal 2 thereby breaking the stick circuit for the approach relay AL at the contact 55 of this signal 2 and thereby locking the switch machine against further operation and'allowing the train on the side track to proceed into the single track section 0. As this train moves into the single track section 0 its passage by the signal 2 will cause the signal which is controlled in accordance with traffic conditions in advance, to be moved to the stop position, and as soon as the rear end of this train passes off of the detector track circuit containing the track relay T the approach relay AL will again be energized through the pick-up circuit heretofore traced which includes the front contact 35 of the track relay T, the contact 5? of the track switch S and the back contact 53 of the track repeater relay TR, all of the contacts 42, 54, 46 and 48 being of course closed by reason of the fact that the signals l, I and 2 are manually held at stop and the fact that the signal E is held at stop by the departing train. With the approach relay .AL now energized the operator is free to return the switch S to the main track position and allow the train occupying the main track of the passing siding PS to follow the other train into the single track section 0.

Summarizing the various operating features of the control for the approach locking relay AL, this relay AL may be energized if all of the signals associated with the switch machine are at stop and the approach section for west bound trains is unoccupied. This relay AL may be picked up for a moment after occupancy of the detector track circuit and may then be stuck up, namely, during the time when the track relay '1 has already picked up but the repeater relay TR has not yet picked up, due to the departure of an east bound train on the main track as manifested by the energized condition of the stick relay 2S or when the train under consideration has passed or is passing into or out of the side track of the passing siding PS, as manifested by switch box contact 51. It is of course understood that for convenience an approach section for west bound trains only has been shown equipped with an approach relay EA, and that a similar approach relay may be used for the approach section for east bound trains, and similarly that a stick relay controlled in exactly the same way for west bound trains as the stick relay 2S is controlled for east bound trains, may be added if desired, these additional devices for facilitating the progress of trafiic over the system having for convenience been omitted.-

Having thus shown and described rather specifically one particular embodiment of the present invention, it is desired to be understood that the particular embodiment selected to exemplify the present invention has been chosen to facilitate description of the invention, and that it has not been selected for the purpose of illustrating the scope of the invention or the exact construction preferably employed in practicing the same, and it is further desired to be understood that various changes, modifications and additions may be made to adapt the invention to the particular problem encountered in practicing the same, all without departing from the spirit or scope of the invention or the idea of means underlying the same, except as demanded by the scope of the following claims.

What I claim as new is:-

1. In combination, a distant track switch, a switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local oflice, and locking means for preventing operation of said switch machine including a stick relay having a pick-up circuit including a front contact of a detector track relay associated with said track switch and a back contact of a slow acting relay repeating said track relay.

2. In combination, a distant track switch, a switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local office, and locking means for preventing operation of said switch machine including a stick relay having a pick-up circuit including a front contact of a detector track relay associated with said track switch, a back contact of a slow acting relay repeating said track relay and having a stick circuit which can be closed only if all of the signals associated with said track switch are at stop.

3. In combination, a distant track switch, a switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local oifice, and locking means for preventing operation of said switch machine including a stick relay having a pickup circuit including a front contact of a detector track relay associated with said track switch, a back contact of a slow acting relay repeating said track relay and a front contact of a directional stick relay.

4. In combination, a distant track switch, a switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local office, and locking means for preventing operation of said switch machine including a stick relay having a pick-up circuit including a front contact of a detector track relay associated with said track switch, a back contact of a slow acting relay repeating said track relay, a front contact of a directional stick relay and having a stick circuit including contacts closed only if all of the way side signals associated with said track switch are at stop.

5. In combination, a distant track switch, a switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local oiiice, and locking means for preventing operation of said switch machine including a stick relay which if deenergized locks said switch machine against operation, and a particular pick-up circuit for said stick relay which can be closed only if a detector track repeater relay associated with said track switch is deenergized and a directional stick relay is energized.

6. In combination, a distant track switch, a switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local ofiice, and locking means for preventing operation of said. switch machine including a stick relay which if deenergized locks said switch machine against operation, a particular pick-up circuit for said stick relay including a front contact of a detector track relay associated with said track switch and including a contact closed only if said track switch assumes the reverse position.

'7. In combination; a distant track switch; a switch machine for operating said track switch; means for manually controlling operation of said switch machine from a local office; and locking means for preventing operation of said switch machine including a stick relay which is decriergized locks said switch machine against operation; a pick-up circiut for said stick relay closed only if the following three conditions prevail, a detector track relay associated with said track switch has been energized for less than a predetermined period of time, said track switch assumes the reverse position, and all of the signals associated with said track switch assume the stop position.

8. In combination, a distant track switch, a switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local oifice, and approach locking means ineffective if a detector track circuit associated with asid track switch has been deenergized and fireenergized with said track switch assuming its reverse position since a signal associated with said track switch has last assumed a proceed position.

9. In combination, a distant track switch, a switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local oflice, and approach locking means rendered ineifective if a detector track circuit associated with said track switch has been deenergized and reenergized simultaneously with a directional stick relay assuming its energized position and since a signal associated with said track switch has last assumed a proceed position.

10. In combination, a distant track switch, a switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local office, and approach locking means rendered ineffective if a detector track circuit associated with said track switch has been deenergized and then reenergized simultaneously with said track switch assuming the reverse position or with a directional stick relay assuming its energized position and since a signal associated with said track switch has last assumed a proceed position.

11. In combination, a directional stick relay for manifesting the direction of movement of a train, two adjacent track sections, a relay for each section deenergized during occupancy of the section with which it is associated, a slow acting device which assumes its deenergized position a short time after occupancy of one of said sections, and a pick-up circuit for said stick relay including in series back contacts of said relays and a front contact of said slow acting device.

12. In combination, a directional stick relay for manifesting the direction of movement of a train, two adjacent track sections, a relay for each section deenergized during occupancy of the section with which it is associated, a slow acting device which assumes its deenergized position a short time after occupancy of one of said sections, a pick-up circuit for said stick relay including in series back contacts of said relays and a front contact of said slow acting device, and a stick circuit for said stick relay including a back contact of said slow acting device.

13. In combination, a stretch of railway ine eluding a detector track section having a detector track relay, a switch leading from the detector track section, a route locking relay to control the operation of said switch arranged to permit operation of the switch when energized and to prevent operation of the switch when tie-energized, means to at time de-energize the route locking relay, a slow-acting relay controlled by a contact of said detector track relay and having a contact closed only when the detector track section has been shunted a given interval of time, and a releasing circuit including said contact and effective under certain conditions to re-energize said route locking relay.

14. In combination, a stretch of railway including a detector track section, a detector track relay for said section, a switch leading from the detector track section, a route locking relay to control the operation of the switch arranged to permit operation of the switch when energized and to prevent operation of the switch when de-energized, means to at times de-energize the route locking relay, a slow-acting relay controlled by a contact of said detector track relay and having a contact closed only when the detector track section has been shunted for a predetermined time and said contact remaining open when the detector track section is but momentarily shunted, and a releasing circuit including said contact and effective under certain conditions to re-energize said route locking relay.

15. In a system of approach locking for poweroperated track switches, in combination, a detector track circuit at a switch having a track relay, locking means including a stick relay at the switch permitting operation of the switch when energized and preventing such operation when de-energized, a slow-acting relay controlled by the detector track circuit and closing its contacts only after said track circuit has been occupied for an appreciable time interval, and an energizing circuit for said stick relay including in series a front contact of the detector track relay and the contacts of said slowacting relay.

16. In a traffic controlling system for railroads, in combination, a power-operated track switch, a detector track circuit at the switch, an approach track section adjacent thereto, signals governing traflic over the switch, means for manually controlling the operation of said switch from a distant point, an approach locking relay acting unless energized to prevent operation of said switch, an energizing circuit for said locking relay closed at one part only if said signals indicate stop, and means effective to close said circuit at another part for a predetermined time only, and only if a train has occupied said detector track circuit for a time interval and then passes entirely into said adjoining approach track section.

17. In an approach locking system, in combination, a power-operated track switch, a detector track circuit at the switch having a track relay, signals governing traffic over the switch, a lock relay permitting operation of the switch if energized and preventing such operation if de-energized, an energizing circuit for the lock relay closed at one part only if said signals indicate stop, and means for closing said energizing circuit at another part for a predetermined time only, and then only after said detector track relay has been de-energized for a time and is then energized.

18. In combination, a stretch of railway including a railway switch and divided into a track section adjacent the switch, and a track section in advance of the switch, a signal to govern trafilc over the switch, a route locking relay to control the operation of the switch and acting to permit operation of the switch when energized and to prevent such operation when de-energized, means responsive to the clearing of the signal to ale-energize said relay, a slowacting relay controlled by the track section adjacent the switch and closing its contacts only after said track section has been occupied for an appreciable period of time, and an energizing circuit for said route locking relay including contacts of said slow-acting relay and closed only when a train passes entirely out of the track section adjacent the switch and into the track section in advance of the switch.

19. In combination, a distant track switch, a

switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local office, and locking means for preventing operation of said switch machine including a stick relay which if deenergized locks said switch machine against operation, a particular pick-up circuit for said stick relay closed only if a detector track relay associated with said track switch has just become energized and then only if said track switch then assumes the reverse position.

20. In combination, a distant track switch, a switch machine for operating said track switch, means for manually controlling operation of said switch machine from a local oflice, and locking means for preventing operation of said switch machine including a stick relay which if deenergized locks said switch machine against operation, a particular pick-up circuit for said stick relay including a front contact of a detector track relay associated with said track switch, and including a contact closed only if said track switch assumes the reverse position, and including a contact closed only if a signal governing traffic over said switch assumes the stop positionv DONALD W. MERSEREAU. 

